Also (in theory), lets say if I had a 100aH 12v btarety and was charging it with a 8amp 18v solar panel (144W)

Also (in theory), lets say if I had a 100aH 12v btarety and was charging it with a 8amp 18v solar panel (144W), it would take me 12.5 hours to charge it, right?(100 divided by 8). Is my math correct there or is it wrong? I do realize that I wouldn't get a continuous output from solar panel like that at 8amps and 18 volts since sun is weaker in the morning and afternoon, and strongest around midday.
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Belismart Answer:
it depends on the sunshine condition ,12.5hours is only a theory data ,in fact,the charging is not like that,
it has big relationship to the voltage of battery ,if the battery voltage is very low level ,the charge controller will boost the voltage and use high current to charge the battery ,usuallly the boost charging will last 2hours